It may all be loaded into RAM if it is small enough and there is enough RAM. But even so, every change (commit) must be saved to a non-volatile medium such as a hard disc, so that the system can recover it following an outage.

But you are right that deleting direct from the database can cause a crash. When say a user account is deleted directly, any post by that user will still link back to the account. and if someone views the post & clicks through, the software will probably assume that the account is still there to be linked to. If it isn't, expect the unexpected, such as a crash. Safer to delete posts & other fingerprints first, then the account. GUI tool designers tend to think of these sorts of things, so mandraulic GUIs tend to be more robust than direct database queries (e.g. allowing admins to lock the account but leaving out a "delete" button). And usually mandraulics is the only way to drive the GUI.

The only reason why I asked the question in the first place was
because of the recent attack of spammers. As I wrote earlier I
am no expert on database related stuff but I can see events
that might occur on large sized database files loaded into
memory.

By adding new spammers, then, them being deleted just
increases memory load which eventually overruns into a disk
based swapfile and/or causes system lock up or crash due to
out of memory error. Much akin to a buffer overrun, but on
a much larger scale...

guy wrote:But you are right that deleting direct from the database can cause a crash. When say a user account is deleted directly, any post by that user will still link back to the account. and if someone views the post & clicks through, the software will probably assume that the account is still there to be linked to.

When a user is deleted their posts still appear with their username, but there is no profile link, so you can't try to view a non-existent user that way. If you load the page while they are still a user but follow the link after they have been deleted, you just get a no such user page.

"Insanity: doing the same thing over and over again and expecting different results." (Albert Einstein)

It was so nice and quiet here with you absent fishy one, what have we done wrong to get you back? Or rather: what went wrong elsewhere that made you come back, gotten your ar*e kicked around in that place?

It was so nice and quiet here with you absent fishy one, what have we done wrong to get you back? Or rather: what went wrong elsewhere that made you come back, gotten your ar*e kicked around in that place?

Surely you noticed that 1sf reappeared just around the time of the spam flood? Coincidence? I think not!